1. Field of the Invention
The present invention relates to a machine for crimping a workpiece, such as a coupling on a hose; a crimping die assembly; and a method for their use.
2. Prior Art Statement
Crimping machines, together with associated crimping dies and pusher assemblies, are used in those applications where an evenly distributed, circumferentially applied force is needed to reduce the diameter of a workpiece without radial distortion. In order to provide an evenly distributed, circumferentially applied force, crimping machines conventionally employ crimping dies comprising a plurality of die fingers which are disposed around the workpiece, and have a curved inside surface adjacent the workpiece which substantially matches the curvature of the workpiece. A ram and driving means are provided to apply a pressing force to the crimping die through a pusher assembly, the pusher assembly being provided to control the amount of the crimp and to assure that the pressing forces of the ram are applied evenly to the die assembly. Means are provided for transferring the linear forces of the ram into radially applied forces on each of the die fingers, causing the die fingers to move uniformly to reduce the diameter of the die fingers such that the die fingers each contact the workpiece with substantially equal force.
Because of the large variety of sizes and types of work pieces that require crimping, prior art crimping devices require a large number of crimping dies, a variety of pusher assemblies, and means by which the operator controls the pressure applied to the workpiece in the crimping operation.
Geizman, in U.S. Pat. No. 3,568,494, teaches a crimping machine having radially disposed crimping jaws and a crimping ring having an internal conical shape for moving said crimping jaws radially inward.
Herndon et al, in U.S. Pat. No. 3,762,209, teach a crimping apparatus having a die head which moves on a central horizontal longitudinal axis and has a plurality of spaced slots therein, each slot having an associated die finger. Each die finger is supported independently within its slot for movement transverse to the longitudinal axis. Each die finger has a spring associated externally therewith for holding each die finger in its slot.
Chen et al, in U.S. Pat. No. 3,851,514, teach a machine for crimping a fitting onto a hose by means of a contractible collet assembly driven by a reciprocal ram using a downward stroke. The ram includes a pusher assembly including first and second pusher members. The collet assembly includes a plurality of segments or jaws.
Kimble et al, in U.S. Pat. No. 4,244,091, teach a hose crimping apparatus which uses radially directed crimping dies and an associated cam surface, and a ram for moving the dies relative to the cam surface in an upward stroke. The apparatus has an associated locator mounted adjacent an outer platform for controlling the length of the ram stroke.
Lillbacka et al, in U.S. Pat. No. 4,250,607, teach a machine for pressing hose couplings onto hoses radially from the circumference toward the center. The machine comprises a revolving disk in which pressing tools can be detachably fastened. The machine uses a programming or manual control device for controlling the stroke length in the pressing operation.
Gunning, in U.S. Pat. No. 4,285,228, teaches a crimping machine in which a ram is driven horizontally to crimp a workpiece using a crimping die assembly that comprises two sub-assemblies. Each sub-assembly has a plurality of die fingers fixed to a mounting plate having slots centrally disposed in grooves.